Lifting platform



June 1l, 1940. K. KLEMM LIFTING PLATFORM Filed Nov. 50, 1937 (Fn @Lf/rnb) Jnrenfor Patented June l1, 1940 UNITED STATESv 2,204,365 LIFTING PLATFORM Karl Klemm, Dresden, Germany Application November so, 1937, serial No. 177,323

In France October 28, 1936 1 claim.- (ci. 121-16) This invention relates to a lifting platform for hydraulic'and pneumatic operation, which serves particularly for raising vehicles.

The platform is operated by means of compressed air and substantiallycomprises an outer cylinder which after installation of the outfit is arranged in the ground or in some other suitable manner and a' piston which slides in the cylinder and on its top is `provided with supports for a l0 vehicle. i

The invention affords the advantage that the' piston moves in the cylinder by means of several guides, so that greater safety in operation and longer life of the outfit are attained. Further-A more, the cylinder is in communication with means -for conducting compressed air under the piston.

The guides provided between the cylinder and the piston preferably operate in different planes,

and the guides, which are independent of one another, can be subdivided into partial guides.

Another feature of the invention is that two independently acting oil brakes are provided for controlling the motion of the piston, the construction being preferably such that the piston moves in the upper portion of the cylinder in suitable inserted guide members and at its lower end is provided with a pistonlike guide memberv which slides in the cylinder and prevents tipping of the piston and which possesses oily passages forming a part of the oil brake.

The upper endof the cylinder may be fitted with a packing for sealing the working piston and with a stripper which hugs the surface of the piston to remove impurities during the descent of the stage. The stripper edge is formed of a profiled piece of elastic material, as rubber,

l etc., which surrounds the piston and has stripper edge of Wedgelike cross section.

l0 By means of projections, stops, etc., arranged at the lower end of the working piston, which cooperate with parts of the cylinder, the stroke of the piston may be limited.

By way of example, the invention is illus- 5 trated in the accompanying drawing, which shows a sectional view of a lifting platform operated by means of compressed air and oil.

Referring to the drawing, thev working cylinder I having an inwardly curved bottom 2 is dis- 0 posed in a foundation let into the ground. In-

side the cylinder `I aguide ring 3 is arranged which is held in position by the screws l and serves as upper guide for the working piston 5. The lowerv open end of the piston 5 possesses 5 'welded holding pins 8 to which a head formed platform, not shown.

as piston plate 8 is secured by means of the nuts 1, the plate 8 sliding tightly in the cylinder I and serving as a lower piston guide having a central opening 9. Furthermore, additional passages III are provided in the piston head 8 in 5 the space between the cylinder wall I and the piston lwall 5, the passages I0 being so dimenff sioned that they act as a brake `during the lowering motion by offering a certain resistance to the flow of the oil I I which is greater than the 10 escape of air. For conducting compressed yair under the piston 5 onv top of the liquid or oil II means such as a pipe 2| are provided, The pipe 2| passes through the central opening 9 which -is also dimensioned so that a passage is formed be- 15 tween the pipe 22 and the walls of the opening tov bring about a braking action during the lowering motion of the piston. On the outside of the piston 5 stops I2 are secured for limiting the stroke of the piston5 by striking against the 20 guide ring 3. i

.The piston 5 is shut off airand liquid-tight by the covering plate I3 and the closure member l and supports on top the bearings I4 for the Above the guide ring 3 packings I5 are provided in the cylinder and held in position by a ring I1 attached to the cylinder by means of the screws I8. A recess of the ring I1 holds a proled piece I8 of elastic material provided with a 30 wedge-like elevation I9 which hugs the outer surface of the piston 5 in the manner of a stripper edge. A holding plate 20 keeps the hollow pressure member I8 in position.

A supply pipe 2| inside the cylinder extends 35 into an ascending pipe 22 which reaches almost up to the upper closed end of the working piston 5. In the embodiment shown the cylinder and the piston 5 are not completely lled with oil. The supply piping 2l communicates with/40 a compressed air producenduring operation of which compressed air is forced under the piston cover I3 to raise the'piston 5 within the cylinderv I. To prevent oil from passing into the compressed air piping 22 the upper end of the as- 45 cen`ding pipe 22 -supports an oil splash plate 5I. Furthermore, the inserted guide ring 3 has a passage 52 extending into avdischarge piping 53. When the lifting device is filled with oil, the

piping 53 is opened to let out the air in the cylin- 50 der and thus prevent the formation of` air pockets. During operation compressed air is forced through the pipes 2|, 22 into the piston 5 which is thus raised. To lower the device the air is let out of the piston or cylinder, so'that 55 the piston drops down by its own weight whilst the thin channels I0 and the passage 9 have a braking eiect. y

I claim:

A lifting platform for vehicles, comprising an outer cylinder, a hollow piston .sliding in the cylinder and closed on top, supports on the piston for holding vehicles, a liquid nearly filling the piston and cylinder, means for conducting compressed air under the piston on top of the liquid, a guide formed at the upper end of the cylinder for said hollow piston, ahead` provided at the lower end of the piston and extending beyond the 

